A sustainable treatment for wood preservation: enzymatic grafting of wood extractives

Natural extractives are proposed as potential sustainable bioactive compounds for wood preservative formulations and an enzyme-mediated reaction is employed to fix them onto the wood surface. This environmentally friendly process takes place thanks to the activity of the laccase enzyme and leads to the formation of covalent bonds between these compounds and the wood itself. This then diminishes the problem of its future leaching, giving rise to long-lasting wood protection treatments. Overall, our data show suitable biocidal properties for the raw extracts of Pinus spp. and Criptomeria japonica. Phenolic compounds such as pinosylvin, pinosylvin monomethyl ether, pinocembrin, naringenin and pinobanksin were found in the extracts of pine together with totarol and sugiol in the C. japonica extract and could explain the anti-fungal properties found. Fungal tests have revealed mass losses below 7% for wood treated with the toluene extracts of Pinus spp. and the ethanolic extract of C. japonica, pointing to this enzymatic green methodology as a promising alternative in the wood preservation field. Furthermore, potential inclusion of these enzymatic strategies in the wood industry today is discussed and analyzed in a "green" scenario.